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Chen 5 Expires: July 19, 2021 Huawei 6 January 15, 2021 8 Operations, Administration and Maintenance (OAM) for Deterministic 9 Networks (DetNet) with MPLS Data Plane 10 draft-ietf-detnet-mpls-oam-02 12 Abstract 14 This document defines format and use principals of the Deterministic 15 Network (DetNet) service Associated Channel (ACH) over a DetNet 16 network with the MPLS data plane. The DetNet service ACH can be used 17 to carry test packets of active Operations, Administration, and 18 Maintenance protocols that are used to detect DetNet failures and 19 measure performance metrics. 21 Status of This Memo 23 This Internet-Draft is submitted in full conformance with the 24 provisions of BCP 78 and BCP 79. 26 Internet-Drafts are working documents of the Internet Engineering 27 Task Force (IETF). Note that other groups may also distribute 28 working documents as Internet-Drafts. The list of current Internet- 29 Drafts is at https://datatracker.ietf.org/drafts/current/. 31 Internet-Drafts are draft documents valid for a maximum of six months 32 and may be updated, replaced, or obsoleted by other documents at any 33 time. It is inappropriate to use Internet-Drafts as reference 34 material or to cite them other than as "work in progress." 36 This Internet-Draft will expire on July 19, 2021. 38 Copyright Notice 40 Copyright (c) 2021 IETF Trust and the persons identified as the 41 document authors. All rights reserved. 43 This document is subject to BCP 78 and the IETF Trust's Legal 44 Provisions Relating to IETF Documents 45 (https://trustee.ietf.org/license-info) in effect on the date of 46 publication of this document. Please review these documents 47 carefully, as they describe your rights and restrictions with respect 48 to this document. Code Components extracted from this document must 49 include Simplified BSD License text as described in Section 4.e of 50 the Trust Legal Provisions and are provided without warranty as 51 described in the Simplified BSD License. 53 Table of Contents 55 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2 56 2. Conventions used in this document . . . . . . . . . . . . . . 2 57 2.1. Terminology and Acronyms . . . . . . . . . . . . . . . . 3 58 2.2. Keywords . . . . . . . . . . . . . . . . . . . . . . . . 4 59 3. Active OAM for DetNet Networks with MPLS Data Plane . . . . . 4 60 3.1. DetNet Active OAM Encapsulation . . . . . . . . . . . . . 5 61 3.2. DetNet Replication, Elimination, and Ordering Sub- 62 functions Interaction with Active OAM . . . . . . . . . . 7 63 4. Use of Hybrid OAM in DetNet . . . . . . . . . . . . . . . . . 7 64 5. OAM Interworking Models . . . . . . . . . . . . . . . . . . . 7 65 5.1. OAM of DetNet MPLS Interworking with OAM of TSN . . . . . 8 66 5.2. OAM of DetNet MPLS Interworking with OAM of DetNet IP . . 9 67 6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 9 68 7. Security Considerations . . . . . . . . . . . . . . . . . . . 9 69 8. Acknowledgment . . . . . . . . . . . . . . . . . . . . . . . 9 70 9. References . . . . . . . . . . . . . . . . . . . . . . . . . 9 71 9.1. Normative References . . . . . . . . . . . . . . . . . . 9 72 9.2. Informational References . . . . . . . . . . . . . . . . 10 73 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 12 75 1. Introduction 77 [RFC8655] introduces and explains Deterministic Networks (DetNet) 78 architecture and how the Packet Replication and Elimination function 79 (PREF) can be used to ensure low packet drop ratio in DetNet domain. 81 Operations, Administration and Maintenance (OAM) protocols are used 82 to detect, localize defects in the network, and monitor network 83 performance. Some OAM functions, e.g., failure detection, work in 84 the network proactively, while others, e.g., defect localization, 85 usually performed on-demand. These tasks achieved by a combination 86 of active and hybrid, as defined in [RFC7799], OAM methods. 88 Also, this document defines format and use principals of the DetNet 89 service Associated Channel over a DetNet network with the MPLS data 90 plane [I-D.ietf-detnet-mpls]. 92 2. Conventions used in this document 93 2.1. Terminology and Acronyms 95 The term "DetNet OAM" used in this document interchangeably with 96 longer version "set of OAM protocols, methods and tools for 97 Deterministic Networks". 99 CW Control Word 101 DetNet Deterministic Networks 103 d-ACH DetNet Associated Channel Header 105 d-CW DetNet Control Word 107 DNH DetNet Header 109 GAL Generic Associated Channel Label 111 G-ACh Generic Associated Channel 113 OAM: Operations, Administration and Maintenance 115 PREF Packet Replication and Elimination Function 117 POF Packet Ordering Function 119 PW Pseudowire 121 RDI Remote Defect Indication 123 E2E End-to-end 125 CFM Connectivity Fault Management 127 BFD Bidirectional Forwarding Detection 129 TSN Time-Sensitive Network 131 F-Label A Detnet "forwarding" label that identifies the LSP used to 132 forward a DetNet flow across an MPLS PSN, e.g., a hop-by-hop label 133 used between label switching routers (LSR). 135 S-Label A DetNet "service" label that is used between DetNet nodes 136 that implement also the DetNet service sub-layer functions. An 137 S-Label is also used to identify a DetNet flow at DetNet service sub- 138 layer. 140 Underlay Network or Underlay Layer: The network that provides 141 connectivity between the DetNet nodes. MPLS network providing LSP 142 connectivity between DetNet nodes is an example of the underlay 143 layer. 145 DetNet Node - a node that is an actor in the DetNet domain. DetNet 146 domain edge node and node that performs PREF within the domain are 147 examples of DetNet node. 149 2.2. Keywords 151 The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", 152 "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and 153 "OPTIONAL" in this document are to be interpreted as described in BCP 154 14 [RFC2119] [RFC8174] when, and only when, they appear in all 155 capitals, as shown here. 157 3. Active OAM for DetNet Networks with MPLS Data Plane 159 OAM protocols and mechanisms act within the data plane of the 160 particular networking layer. And thus it is critical that the data 161 plane encapsulation supports OAM mechanisms in such a way to comply 162 with the OAM requirements listed in [I-D.tpmb-detnet-oam-framework]. 163 One of such examples that require special consideration is 164 requirement #5: 166 DetNet OAM packets MUST be in-band, i.e., follow precisely the 167 same path as DetNet data plane traffic both for unidirectional and 168 bi-directional DetNet paths. 170 The Det Net data plane encapsulation in transport network with MPLS 171 encapsulation specified in [I-D.ietf-detnet-mpls]. For the MPLS 172 underlay network, DetNet flows to be encapsulated analogous to 173 pseudowires (PW) over MPLS packet switched network, as described in 174 [RFC3985], [RFC4385]. Generic PW MPLS Control Word (CW), defined in 175 [RFC4385], for DetNet displayed in Figure 1. 177 0 1 2 3 178 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 179 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 180 |0 0 0 0| Sequence Number | 181 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 183 Figure 1: DetNet Control Word Format 185 PREF in the DetNet domain composed by a combination of nodes that 186 perform replication and elimination sub-functions. The elimination 187 sub-function always uses the S-Label and packet sequencing 188 information, e.g., the value in the Sequence Number field of DetNet 189 CW (d-CW). The replication sub-function uses the S-Label information 190 only. For data packets Figure 2 presents an example of PREF in 191 DetNet domain. 193 1111 11111111 111111 112212 112212 132213 194 CE1----EN1--------R1-------R2-------R3--------EN2----CE2 195 \2 22222/ 3 / 196 \2222222 /----+ 3 / 197 +------R4------------------------+ 198 333333333333333333333333 200 Figure 2: DetNet Data Plane Based on PW 202 3.1. DetNet Active OAM Encapsulation 204 DetNet OAM, like PW OAM, uses PW Associated Channel Header defined in 205 [RFC4385]. Figure 3 displays the encapsulation of a DetNet MPLS 206 [I-D.ietf-detnet-mpls] active OAM packet. 208 +---------------------------------+ 209 | | 210 | DetNet App-Flow | 211 | Payload Packet | 212 | | 213 +---------------------------------+ <--\ 214 | DetNet Associated Channel Header| | 215 +---------------------------------+ +--> DetNet active OAM 216 | S-Label | | MPLS encapsulation 217 +---------------------------------+ | 218 | [ F-Label(s) ] | | 219 +---------------------------------+ <--/ 220 | Data-Link | 221 +---------------------------------+ 222 | Physical | 223 +---------------------------------+ 225 Figure 3: DetNet Active OAM Packet Encapsulation in MPLS Data Plane 227 Figure 4 displays encapsulation of a test packet of an active DetNet 228 OAM protocol in case of MPLS-over-UDP/IP 229 [I-D.ietf-detnet-mpls-over-udp-ip]. 231 +---------------------------------+ 232 | | 233 | DetNet App-Flow | 234 | Payload Packet | 235 | | 236 +---------------------------------+ <--\ 237 | DetNet Associated Channel Header| | 238 +---------------------------------+ +--> DetNet active OAM 239 | S-Label | | MPLS encapsulation 240 +---------------------------------+ | 241 | [ F-label(s) ] | | 242 +---------------------------------+ <--+ 243 | UDP Header | | 244 +---------------------------------+ +--> DetNet data plane 245 | IP Header | | IP encapsulation 246 +---------------------------------+ <--/ 247 | Data-Link | 248 +---------------------------------+ 249 | Physical | 250 +---------------------------------+ 252 Figure 4: DetNet Active OAM Packet Encapsulation in MPLS-over-UDP/IP 254 Figure 5 displays the format of the DetNet Associated Channel Header 255 (d-ACH). 257 0 1 2 3 258 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 259 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 260 |0 0 0 1|Version|Sequence Number| Channel Type | 261 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 263 Figure 5: DetNet Associated Channel Header Format 265 The meanings of the fields in the d-ACH are: 267 Bits 0..3 MUST be 0b0001. This value of the first nibble allows 268 the packet to be distinguished from an IP packet [RFC4928] and a 269 DetNet data packet [I-D.ietf-detnet-mpls]. 271 Version: this is the version number of the d-ACH. This 272 specification defines version 0. 274 Sequence Number: this is unsigned eight bits-long field. The 275 originating DetNet node MUST set the value of the Sequence Number 276 field to a non-zero before packet being transmitted. The 277 originating node MUST monotonically increase the value of the 278 Sequence Number field for the every next active OAM packet. 280 Channel Type: the value of DetNet Associated Channel Type is one 281 of values defined in the IANA PW Associated Channel Type registry. 283 The DetNet flow, according to [I-D.ietf-detnet-mpls], is identified 284 by the S-label that MUST be at the bottom of the stack. Active OAM 285 packet MUST have d-ACH immediately following the S-label. 287 3.2. DetNet Replication, Elimination, and Ordering Sub-functions 288 Interaction with Active OAM 290 At the DetNet service layer, special functions MAY be applied to the 291 particular DetNet flow - PREF to potentially lower packet loss, 292 improve the probability of on-time packet delivery and Packet 293 Ordering Function (POF) to ensure in-order packet delivery. As data 294 and the active OAM packets have the same Flow ID, S-label, sub- 295 functions that rely on sequencing information in the DetNet service 296 layer MUST process 28 MSBs of the d-ACH as the source of the 297 sequencing information for the OAM packet. 299 4. Use of Hybrid OAM in DetNet 301 Hybrid OAM methods are used in performance monitoring and defined in 302 [RFC7799] as: 304 Hybrid Methods are Methods of Measurement that use a combination 305 of Active Methods and Passive Methods. 307 A hybrid measurement method may produce metrics as close to passive, 308 but it still alters something in a data packet even if that is the 309 value of a designated field in the packet encapsulation. One example 310 of such a hybrid measurement method is the Alternate Marking method 311 described in [RFC8321]. Reserving the field for the Alternate 312 Marking method in the DetNet Header will enhance available to an 313 operator set of DetNet OAM tools. 315 5. OAM Interworking Models 317 Interworking of two OAM domains that utilize different networking 318 technology can be realized either by a peering or a tunneling model. 319 In a peering model, OAM domains are within the corresponding network 320 domain. When using the peering model, state changes that are 321 detected by a Fault Management OAM protocol can be mapped from one 322 OAM domain into another or a notification, e.g., an alarm, can be 323 sent to a central controller. In the tunneling model of OAM 324 interworking, usually, only one active OAM protocol is used. Its 325 test packets are tunneled through another domain along with the data 326 flow, thus ensuring the fate sharing among test and data packets. 328 5.1. OAM of DetNet MPLS Interworking with OAM of TSN 330 Active DetNet OAM is required to provide the E2E fault management and 331 performance monitoring for a DetNet flow. Interworking of DetNet 332 active OAM with MPLS data plane with the IEEE 802.1 Time-Sensitive 333 Networking (TSN) domain based on [I-D.ietf-detnet-mpls-over-tsn]. 335 In the case of the peering model is used in the fault management OAM, 336 then the node that borders both TSN and DetNet MPLS domains MUST 337 support [RFC7023]. [RFC7023] specified the mapping of defect states 338 between Ethernet Attachment Circuits (ACs) and associated Ethernet 339 PWs that are part of an end-to-end (E2E) emulated Ethernet service. 340 Requirements and mechanisms described in [RFC7023] are equally 341 applicable to using the peering model to achieve E2E FM OAM over 342 DetNet MPLS and TSN domains. The Connectivity Fault Management (CFM) 343 protocol [IEEE.CFM] or in [ITU.Y1731] can provide fast detection of a 344 failure in the TSN segment of the DetNet service. In the DetNet MPLS 345 domain BFD (Bidirectional Forwarding Detection), specified in 346 [RFC5880] and [RFC5885], can be used. To provide E2E failure 347 detection, the TSN segment might be presented as a concatenated with 348 the DetNet MPLS and the Section 6.8.17 [RFC5880] MAY be used to 349 inform the upstream DetNet MPLS node of a failure of the TSN segment. 350 Performance monitoring can be supported by [RFC6374] in the DetNet 351 MPLS and [ITU.Y1731] in the TSN domains, respectively. Performance 352 objectives for each domain should refer to metrics that additive or 353 be defined for each domain separately. 355 The following considerations are to be realized when using the 356 tunneling model of OAM interworking between DetNet MPLS and TSN 357 domains: 359 o Active OAM test packet MUST be mapped to the same TSN Stream ID as 360 the monitored DetNet flow. 362 o Active OAM test packets MUST be treated in the TSN domain based on 363 its S-label and CoS marking (TC field value). 365 Note that the tunneling model of the OAM interworking requires that 366 the remote peer of the E2E OAM domain supports the active OAM 367 protocol selected on the ingress endpoint. For example, if BFD is 368 used for proactive path continuity monitoring in the DetNet MPLS 369 domain, a TSN endpoint of the DetNet service has also support BFD as 370 defined in [RFC5885]. 372 5.2. OAM of DetNet MPLS Interworking with OAM of DetNet IP 374 Interworking between active OAM segments in DetNet MPLS and DetNet IP 375 domains can also be realized using either the peering or the 376 tunneling model, as discussed in Section 5.1. Using the same 377 protocol, e.g., BFD, over both segments, simplifies the mapping of 378 errors in the peering model. To provide the performance monitoring 379 over a DetNet IP domain STAMP [RFC8762] and its extensions 380 [I-D.ietf-ippm-stamp-option-tlv] can be used. 382 6. IANA Considerations 384 This document does not have any requests for IANA allocation. This 385 section can be deleted before the publication of the draft. 387 7. Security Considerations 389 Additionally, security considerations discussed in DetNet 390 specifications: [RFC8655], [I-D.ietf-detnet-security], 391 [I-D.ietf-detnet-mpls] are applicable to this document. Security 392 concerns and issues related to MPLS OAM tools like LSP Ping 393 [RFC8029], BFD over PW [RFC5885] also apply to this specification. 395 8. Acknowledgment 397 Authors extend their appreciation to Pascal Thubert for his 398 insightful comments and productive discussion that helped to improve 399 the document. 401 9. References 403 9.1. Normative References 405 [I-D.ietf-detnet-mpls] 406 Varga, B., Farkas, J., Berger, L., Malis, A., Bryant, S., 407 and J. Korhonen, "DetNet Data Plane: MPLS", draft-ietf- 408 detnet-mpls-13 (work in progress), October 2020. 410 [I-D.ietf-detnet-mpls-over-udp-ip] 411 Varga, B., Farkas, J., Berger, L., Malis, A., and S. 412 Bryant, "DetNet Data Plane: MPLS over UDP/IP", draft-ietf- 413 detnet-mpls-over-udp-ip-08 (work in progress), December 414 2020. 416 [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate 417 Requirement Levels", BCP 14, RFC 2119, 418 DOI 10.17487/RFC2119, March 1997, 419 . 421 [RFC7023] Mohan, D., Ed., Bitar, N., Ed., Sajassi, A., Ed., DeLord, 422 S., Niger, P., and R. Qiu, "MPLS and Ethernet Operations, 423 Administration, and Maintenance (OAM) Interworking", 424 RFC 7023, DOI 10.17487/RFC7023, October 2013, 425 . 427 [RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC 428 2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174, 429 May 2017, . 431 [RFC8655] Finn, N., Thubert, P., Varga, B., and J. Farkas, 432 "Deterministic Networking Architecture", RFC 8655, 433 DOI 10.17487/RFC8655, October 2019, 434 . 436 9.2. Informational References 438 [I-D.ietf-detnet-mpls-over-tsn] 439 Varga, B., Farkas, J., Malis, A., and S. Bryant, "DetNet 440 Data Plane: MPLS over IEEE 802.1 Time Sensitive Networking 441 (TSN)", draft-ietf-detnet-mpls-over-tsn-05 (work in 442 progress), December 2020. 444 [I-D.ietf-detnet-security] 445 Grossman, E., Mizrahi, T., and A. Hacker, "Deterministic 446 Networking (DetNet) Security Considerations", draft-ietf- 447 detnet-security-13 (work in progress), December 2020. 449 [I-D.ietf-ippm-stamp-option-tlv] 450 Mirsky, G., Min, X., Nydell, H., Foote, R., Masputra, A., 451 and E. Ruffini, "Simple Two-way Active Measurement 452 Protocol Optional Extensions", draft-ietf-ippm-stamp- 453 option-tlv-10 (work in progress), November 2020. 455 [I-D.tpmb-detnet-oam-framework] 456 Mirsky, G., Theoleyre, F., Papadopoulos, G., and C. 457 Bernardos, "Framework of Operations, Administration and 458 Maintenance (OAM) for Deterministic Networking (DetNet)", 459 draft-tpmb-detnet-oam-framework-00 (work in progress), 460 January 2021. 462 [IEEE.CFM] 463 IEEE, "Connectivity Fault Management clause of IEEE 464 802.1Q", IEEE 802.1Q, 2013. 466 [ITU.Y1731] 467 ITU-T, "OAM functions and mechanisms for Ethernet based 468 Networks", ITU-T Recommendation G.8013/Y.1731, November 469 2013. 471 [RFC3985] Bryant, S., Ed. and P. Pate, Ed., "Pseudo Wire Emulation 472 Edge-to-Edge (PWE3) Architecture", RFC 3985, 473 DOI 10.17487/RFC3985, March 2005, 474 . 476 [RFC4385] Bryant, S., Swallow, G., Martini, L., and D. McPherson, 477 "Pseudowire Emulation Edge-to-Edge (PWE3) Control Word for 478 Use over an MPLS PSN", RFC 4385, DOI 10.17487/RFC4385, 479 February 2006, . 481 [RFC4928] Swallow, G., Bryant, S., and L. Andersson, "Avoiding Equal 482 Cost Multipath Treatment in MPLS Networks", BCP 128, 483 RFC 4928, DOI 10.17487/RFC4928, June 2007, 484 . 486 [RFC5880] Katz, D. and D. Ward, "Bidirectional Forwarding Detection 487 (BFD)", RFC 5880, DOI 10.17487/RFC5880, June 2010, 488 . 490 [RFC5885] Nadeau, T., Ed. and C. Pignataro, Ed., "Bidirectional 491 Forwarding Detection (BFD) for the Pseudowire Virtual 492 Circuit Connectivity Verification (VCCV)", RFC 5885, 493 DOI 10.17487/RFC5885, June 2010, 494 . 496 [RFC6374] Frost, D. and S. Bryant, "Packet Loss and Delay 497 Measurement for MPLS Networks", RFC 6374, 498 DOI 10.17487/RFC6374, September 2011, 499 . 501 [RFC7799] Morton, A., "Active and Passive Metrics and Methods (with 502 Hybrid Types In-Between)", RFC 7799, DOI 10.17487/RFC7799, 503 May 2016, . 505 [RFC8029] Kompella, K., Swallow, G., Pignataro, C., Ed., Kumar, N., 506 Aldrin, S., and M. Chen, "Detecting Multiprotocol Label 507 Switched (MPLS) Data-Plane Failures", RFC 8029, 508 DOI 10.17487/RFC8029, March 2017, 509 . 511 [RFC8321] Fioccola, G., Ed., Capello, A., Cociglio, M., Castaldelli, 512 L., Chen, M., Zheng, L., Mirsky, G., and T. Mizrahi, 513 "Alternate-Marking Method for Passive and Hybrid 514 Performance Monitoring", RFC 8321, DOI 10.17487/RFC8321, 515 January 2018, . 517 [RFC8762] Mirsky, G., Jun, G., Nydell, H., and R. Foote, "Simple 518 Two-Way Active Measurement Protocol", RFC 8762, 519 DOI 10.17487/RFC8762, March 2020, 520 . 522 Authors' Addresses 524 Greg Mirsky 525 ZTE Corp. 527 Email: gregimirsky@gmail.com 529 Mach(Guoyi) Chen 530 Huawei 532 Email: mach.chen@huawei.com